Applied
Speciation offers ultra trace mercury speciation analysis by ion
chromatography cold vapor inductively coupled plasma mass
spectrometry (IC-CV-ICP-MS). Chromatographic separation of the
mercury species allows for the quantitation of methyl mercury, Hg
(II), phenyl mercury, and other soluble mercury species in a single
analytical run. Employing the cold vapor reaction prior to
introduction into the ICP-MS yields an almost spectral free
interference ion beam while reaching an almost 100% transfer
efficiency of the mercury into the system. This equates to ultra
trace detection limits (0.5ng/L) without the need for sample
dilution in most cases. This robust method of analysis allows for
maximum automation which significantly decreases the per sample cost
for analysis while increasing confidence in the results due to the
capacity to perform mass balances.

Ultra low mercury speciation analysis of
routine aqueous samples has been well established with EPA Method
1630 using distillation followed by derivatization, gas
chromatography cold vapor atomic fluorescence spectrometry
(GC-CV-AFS). The distillation process associated with EPA Method
1630 requires the generation of a “fudge factor” due to the
operationally defined performance of the procedure. Although the
distillation efficiency is fairly constant the necessity for data
manipulation due to method limitations is not often desired in
analytical chemistry.

Methyl mercury is not readily purged from the
distillate which requires derivatization (ethylation) with sodium
tetraethyl borate (NaBEt4). The reaction between the
ethylating agent and methyl mercury is a non-specific reaction. The
presence of organic compounds, which can be transferred from the
sample to the distillate, can interfere with the derivatization
efficiency producing a low bias result. The prevalence of this
interference is low; however, quality control is rarely performed on
every same which can result in biased results for more complicated
matrices.

The IC-CV-ICP-MS method employed at Applied
Speciation eliminates the need for distillation and derivatization
resulting in a more robust analytical method. Monitoring other
mercury isotopes, inclusion of internal standards and expanding the
analyte list to include all dissolved mercury species equates to
greater confidence in the data. The capability of quantitating MMHg,
Hg (II), and Ph-Hg with IC-CV-ICP-MS also allows for monitoring
species conversion during preparation and analysis which could not
be accomplished with EPA Method 1630.

If you have a need for mercury speciation
analysis, feel free to contact us to find out how Applied Speciation
and Consulting can save you time and money with your next project (info@appliedspeciation.com).